This invention relates to devices for retaining the top peripheral edge portion of a watertight liner such as the type used in the construction of swimming pools.
A common and well known method of constructing swimming pools comprises the erection or placement of fixed walls and a floor for the pool which are not watertight but which have sufficient structural strength to contain the water. A pool liner is required in such a pool to make it watertight. The liner is constructed from a waterproof sheet material which often consists of vinyl. The liner has a top peripheral edge portion that corresponds with or is located adjacent to the top of the structural walls of the pool. Various methods have been proposed and used to attach the top peripheral edge of the liner to the top of the pool walls in order to ensure that the liner does not slip down below the water line. Many of these methods involve the use of preformed coping members which finish and round the top peripheral edge of the pool for safety and attractive appearance. Commonly, a groove or slot is provided in this coping for receiving a thickened bead formed on the top peripheral edge portion of the liner. A longitudinal flange located adjacent to the mouth of the slot engages a corresponding flange or lip in the liner bead in order to retain the liner edge. One difficulty with such a method arises from the fact that in order to insert the liner bead into the slot, the bead and slot must be dimensioned loosely. This fact can result in the liner being pulled out of the coping slot. If this should occur, the liner normally cannot be reinserted into the coping without draining the pool.
In U.S. Pat. No. 4,158,244 issued June 19, 1979 to Timerax Holdings Ltd. the retaining element, in addition to having a holding channel for accommodating the liner bead, has a generally cylindrical hinge channel communicating with the holding channel. An elongate resilient U-shaped insert is located in the hinge channel. This insert has an outward closing element depending from the hinge channel to partially close a longitudinal outward slot defined by the two channels. A rib arrangement is provided to prevent rotation of the insert in the hinge channel. The closing element is biased towards the slot so that, after insertion of the liner bead, the insert engages a stop, partially closes the slot, and retains the liner bead.
British Pat. No. 1,395,602 also discloses a strip attachment for securing the edge of a fabric to a surface. The front face of the attachment has a rib that defines the top of a recess for receiving a rod or bead attached to the edge of the fabric. The device of the British patent includes a cover member having an upper section that is inserted between a top projecting portion of the strip attachment and the rib. A front section of the cover member extends over the recess in the strip attachment and the rod therein. The cover member of this patent is provided for appearances only and does not assist in the retention of the rod attached to the edge of the fabric.
It is an object of the present invention to provide a very simple structure for positively retaining the top peripheral edge portion of a pool liner.
It is a further object of the present invention to provide an inexpensive pool liner retainer that employs an elongate clip that is fitted onto a flange of an elongate retaining element in order to partially close a slot in the retaining element and thereby retain a liner bead in the retaining element.